Cranial extradural empyema in the era of computed tomography: a review of 82 cases

Streptococcus intermedius: an underestimated pathogen in brain infection?

Streptococcus intermedius is an oral commensal organism belonging to the Streptococcus anginosus group (SAG). S. intermedius causes periodontitis as well as invasive, pyogenic infection of the central nervous system, pleural space or liver. Compared with other SAG organisms, S. intermedius has a higher mortality as well as a predilection for intracranial infection, suggesting it is likely to possess virulence factors that mediate specific interactions with the host resulting in bacteria reaching the brain. The mechanisms involved are not well described. Intracranial suppuration (ICS) due to S. intermedius infection can manifest as an abscess within the brain parenchyma, or a collection of pus (empyema) in the sub- or extra-dural space. These infections necessitate neurosurgery and prolonged antibiotic treatment and are associated with a considerable burden of morbidity and mortality. The incidence of ICS is increasing in several settings, with SAG species accounting for an increasing proportion of cases. There is a paucity of published literature regarding S. intermedius pathogenesis as well as few published genomes, hampering molecular epidemiological research. This perspective evaluates what is known about the clinical features and pathogenesis of ICS due to S. intermedius and explores hypothetical explanations why the incidence of these infections may be increasing.

A case report of frontal spontaneous epidural hematoma associated with cranial osteomyelitis and epidural abscess due to paranasal sinusitis

Background:

Intracranial epidural hematoma (EDH) is frequently secondary to trauma, but in some rare cases, spontaneous EDH (SEDH) could develop without trauma. Cranial osteomyelitis is an uncommon osseous infection that most frequently presents as a postoperative complication but also rarely originates from paranasal sinusitis and can develop extracranially to form a subperiosteal abscess or intracranially to form an epidural, subdural, or cerebral abscess. Intracranial epidural abscess (EDA) is an uncommon infection that forms in the space between the cranial bone and dura mater. It is rare to have a case of SEDH associated with cranial osteomyelitis and EDA due to paranasal sinusitis.

Case Description:

An 18-year-old male was admitted to the hospital with headache, nausea, and vomiting for 2 days. The patient denied a history of head trauma, operation, and any other infectious and systemic diseases, and he was not taking any medication. CT scan demonstrated a mixed density lenticular mass with some air collection in the frontal region. The axial sinus CT image demonstrated opacification of the left frontal, ethmoid, and maxillary sinuses. An emergency operation confirmed the diagnosis of frontal SEDH associated with EDA and frontal osteomyelitis. The frontal EDH, abscess, and the infected bone were completely removed during the operation without opening the dura. The patient recovered well after receiving 8 weeks of antibiotic therapy, and a cranioplasty was performed 9 months after the craniectomy.

Conclusion:

To the best of our knowledge, SEDH associated with EDA is very rare. It is important to recognize the possibility of SEDH associated with cranial osteomyelitis and EDA due to paranasal sinusitis, and the presence of an EDA should, therefore, be considered in the differential diagnosis of cases of SEDH.

Epidural abscess presenting as severe depression with suicidal ideations: Case report

Background

Epidural abscess (EDA) is an uncommon form of intracranial infection that generally presents with fever, headache, and focal neurologic deficit. Imaging generally reveals a lentiform collection with diffusion restriction on diffusion weighted image. We present an interesting case in which a patient with EDA presented with three weeks of depression with suicidal ideations. The patient displayed no notable infectious signs and the imaging was suggestive of chronic subdural hematoma (SDH) rather than EDA.

Case Description

The patient is a 57-year-old man with past medical history significant for epilepsy and left hemiplegia secondary to remote traumatic brain injury who presented with a three-week history of depression, anxiety, and active suicidal ideation, resulting in psychiatric admission to an outside hospital. He had undergone three previous craniotomies for SDH many years ago and had no significant psychiatric history. Magnetic resonance imaging was consistent with subacute right SDH. On presentation, patient was at neurologic baseline and was afebrile with unremarkable labs. Operative findings demonstrated frank purulence in the epidural space. The patient was treated with antibiotics and both depression and suicidal ideations resolved postoperative day 5.

Conclusions

EDA can present in atypical ways, especially in patients who have undergone previous cranial procedures. Depression is one possible atypical presentation.

Aspiration of parafalcine empyemas with flexible scope

PURPOSE

Subdural empyemas are considered neurosurgical emergencies, and the parafalcine location is particularly insidious. We revised the experience of general surgeons who are used to manage chronic pleural purulent collections with video-assisted thoracoscopy.

METHODS

With a similar technique, we successfully aspirated a parafalcine empyema using a flexible scope avoiding a more invasive craniotomy. A review of the treatment options of empyematous collections is also provided, focusing particularly on the hazardous parafalcine location.

RESULTS

The management of subdural empyemas poses different decision-making problems compared to common brain abscesses, urging a more rapid and holistic surgical treatment with minimally invasive approach. Endoscopic aspiration of parafalcine empyema was followed by complete recovery in our patient.

CONCLUSIONS

Flexible endoscopy is a promising method to obtain complete pus removal even from loculated collections through a bur hole, avoiding large craniotomies and consequent potential complications.

Pediatric intracranial abscesses

Intracranial infections in children are a relatively rare, but potentially severe condition. Because of the potential for rapid deterioration, timely diagnosis and treatment are necessary. These infections are categorized based on their intracranial location: epidural abscess, subdural empyema, and brain abscess. They largely arise from direct extension of adjacent infection, hematogenous seeding, or trauma. Clinical presentations of intracranial infections also vary. However, common signs and symptoms include headache, fever, nausea and vomiting, altered mental status, focal neurologic deficits, and seizures. In general, MRI demonstrates a peripherally enhancing lesion with high signal on diffusion weighted imaging (DWI). Bacterial isolates vary, but most commonly are a single pathogen. Successful treatment requires a multidisciplinary team approach including such modalities as antibiotic therapy and surgical drainage. When possible, open surgical evacuation of the abscess is preferred, however, in cases of deep-seated lesions, or in unstable patients, aspiration has also been performed with good results.

Biodegradable vancomycin-eluting poly[(d,l)-lactide-co-glycolide] nanofibres for the treatment of postoperative central nervous system infection

The incidence of postoperative central nervous system infection (PCNSI) is higher than 5%–7%. Successful management of PCNSI requires a combined therapy of surgical debridement and long-term antibiotic treatment. In this study, Duraform soaked in a prepared bacterial solution was placed on the brain surface of rats to induce PCNSI. Virgin poly[(d,l)-lactide-co-glycolide] (PLGA) nanofibrous membranes (vehicle-control group) and vancomycin-eluting PLGA membranes (vancomycin-nanofibres group) were implanted. The wound conditions were observed and serial brain MRI and pathology examinations were performed regularly. PCNSI was consistently induced in a single, simple step. In the vehicle-control group, most rats died within 1 week, and the survival rate was low (odds ratio = 0.0357, 95% confidence interval = 0.0057–0.2254). The wounds and affected cerebral tissues necrosed with purulence and increased in mass from the resulting PCNSI volumes. Initially, the mean PCNSI volumes showed no significant difference between the two groups. The PCNSI volume in the rats in the vancomycin-nanofibres group significantly decreased (P < 0.01), and the wound appearance was excellent. Pathologic examinations revealed that the necrosis and leukocyte infiltration area decreased considerably. The experimental results suggest that vancomycin-eluting PLGA nanofibres are favourable candidates for treating PCNSI after surgical debridement.

Neuro-intensive care of patients with acute CNS infections

Infections in the central nervous system (CNS) are caused by a wide range of microorganisms resulting in distinct clinical syndromes including meningitis, encephalitis, and pyogenic infections, such as empyema and brain abscess. Bacterial and viral infections in the CNS can be rapidly fatal and can result in severe disability in survivors. Appropriate identification and acute management of these infections often occurs in a critical care setting and is vital to improving outcomes in this group of patients. This review of diagnosis and management of acute bacterial and viral infections in the CNS provides a general approach to patients with a suspected CNS infection and also provides a more detailed review of the diagnosis and management of patients with suspected bacterial meningitis, viral encephalitis, brain abscess, and subdural empyema.

Taming an old enemy: a profile of intracranial suppuration

Intracranial suppurative disorders (ICSDs; brain abscess, empyema, and purulent ventriculitis), have been a scourge through the ages and attempts at curative surgery, as for cranial trauma, are considered to be one of the first true neurosurgical interventions performed. ICSDs, seen initially as a consequence of poor socioeconomic conditions and neglected otorhinogenic infections, predominantly manifest today as postsurgical complications, and/or in immunocompromised patients where they continue to result in significant neurologic morbidity and death. The reduction in the incidence of "old world" classic ICSDs can be attributed to the modernization of society, driven inter alia by a shift from an agricultural to an industrial economic society. It can also be coupled with pivotal achievements in public health and the dramatic developments in medicine in the 20th century. This trend was first noted in developed countries but now, with improved socioeconomic circumstances and globalization of medical technology, it is occurring in the developing regions of the world as well. Although ICSDs have undergone a metamorphosis in their clinical profile and despite their rarity in contemporary "developed world" neurosurgical practice, they still have undoubted potential for fatal consequences and continue to pose a significant challenge to the 21st-century neurosurgeon.

Brain abscess: management and outcome analysis of a computed tomography era experience with 973 patients

OBJECTIVE

Brain abscess (BA) is a neurosurgical emergency and despite significant medical advances, it remains a surgical challenge. A single institution's two decade computed tomography era management experience with BA is reported.

METHODS

A retrospective analysis of patients with BA, admitted to the Department of Neurosurgery, Wentworth Hospital, Durban, KwaZulu-Natal, South Africa, was performed. The medical records were analyzed for demographic, clinical, neuroimaging, neurosurgical and otolaryngology management, microbiological characteristics, and their relationship to outcome.

RESULTS

During a 20-year period (1983-2002), 973 patients were treated. The mean age was 24.36 ± 15.1 years (range: 0.17-72 years) and 74.2% (n = 722) were men. The mean admission Glasgow Coma Score was 12.5 ± 2.83. The majority of BAs were supratentorial (n = 872, 89.6%). The causes were otorhinogenic (38.6%), traumatic (32.8%), pulmonary (7%), cryptogenic (4.6%), postsurgical (3.2%), meningitis (2.8%), cardiac (2.7%), and "other" (8.6%). Surgical drainage was performed in 97.1%, whereas 19 patients had nonoperative management. The incidence of BA decreased during the study period. Patient outcomes were good in 81.3% (n = 791), poor in 5.3% (n = 52), and death (13.4%, n = 130) at discharge. The management morbidity, which included postoperative seizures, was 24.9%. Predictors of mortality were cerebral infarction (odds ratio [OR] 31.1), ventriculitis (OR 12.9), coma (OR 6.8), hydrocephalus (OR 5.1), dilated pupils (OR 4.8), bilateral abscesses (OR 3.8), multiple abscesses (OR 3.4), HIV co-infection (OR 3.2), papilledema (OR 2.6), neurological deterioration (OR 2.4), and fever (OR 1.7).

CONCLUSIONS

Optimal management of BA involves surgical drainage for medium-to-large abscesses (≥2.5 cm) with simultaneous eradication of the primary source, treatment of associated hydrocephalus, and administration of high doses of intravenous antibiotics. The incidence of BA is directly related to poor socioeconomic conditions and therefore, still poses a public health challenge in developing countries.

Intracranial suppuration complicating sinusitis among children: an epidemiological and clinical study

OBJECT

Intracranial abscess is a very infrequent complication of sinusitis among children. Case series, mostly small and focusing on surgical treatment, have appeared in the literature, but there has been no study on the epidemiology of this condition, nor has there been any large-scale study on the intensity of therapy or outcomes.

METHODS

Data were drawn from the Kids' Inpatient Databases for 1997, 2000, 2003, and 2006 and the National Inpatient Sample for 2001. Cases were defined by the conjunction between the diagnostic codes for intracranial abscess and those for acute or chronic sinusitis or mastoiditis.

RESULTS

Eight hundred forty-seven hospital admissions were captured. Over the 10 years of the study, admission rates ranged between 2.74 and 4.38 per million children per year. Boys were affected much more commonly than girls. Black children were affected out of proportion to their presence in the population. The overall incidence seemed to peak in early adolescence. Sinogenic cases had a marked seasonal pattern peaking in winter, but no seasonal variation was seen for otogenic cases. Asthma comorbidity was more prevalent among sinogenic cases. The mortality rate was 2%, and death occurred only among sinogenic cases. Moreover, sinogenic cases tended to require more intensive therapy, as measured by the number of procedures, and there was a trend toward less favorable discharge dispositions. Older patients and black patients were less likely to be discharged directly to home. At least a quarter of the cases were managed without neurosurgical intervention. White patients were treated without neurosurgery more often than others.

CONCLUSIONS

Analysis of administrative data sets has yielded a descriptive picture of intracranial abscess complicating sinusitis among children, but the very low incidence of this condition impedes prospective clinical research directed at practical management issues.

Intracranial epidural abscess of odontogenic origin

Dental infection as a cause of epidural abscess is rare compared with other forms of intracranial suppurations. A 10-year-old boy was seen because of headaches and fever. There was no history of otitis media or sinusitis, but he had sought care for dental complaints. The patient was from an upper-middle-class family, was not immunocompromised, and had no other risk factor for a major infection. A CT brain scan confirmed a frontal epidural abscess. The patient underwent emergency surgery for evacuation of the epidural abscess, followed by antimicrobial therapy. His condition improved remarkably following surgery, with complete resolution of symptoms. He subsequently underwent extraction of 2 teeth following dental review. Dental infection as a cause of intracranial epidural abscess is rare, but should be considered when evaluating patients for intracranial infections. A review of the literature sheds light on the causal relationship and possible pathogenesis of this condition.

Operative intracranial infection following craniotomy

OBJECT

Postoperative infection after cranial surgery is a serious complication that requires immediate recognition and treatment. In certain cases such as postoperative meningitis, the patient can be treated with antibiotics only. In cases that involve a bone flap infection, subdural empyema, or cerebral abscess, however, reoperation is often needed. There has been significant disagreement regarding the incidence of postoperative central nervous system (CNS) infections following cranial surgery. In this paper the authors' goal was to perform a retrospective review of the incidence of CNS infection after cranial surgery at their institution. They focused their review on those patients who required repeated surgery to treat the infection.

METHODS

The authors reviewed the medical records and imaging studies in all patients who underwent a craniotomy or stereotactic drainage for CNS infection over the past 10 years. Subgroup analysis was then performed in patients whose infection was a result of a previous cranial operation to determine the incidence, factors associated with infection, and the type of infectious organism. Patients treated nonoperatively (that is, those who received intravenous antibiotics for postoperative meningitis or cellulitis) were not included. Patients treated for wound infection without intracranial pus were also not included.

RESULTS

During the study period from January 1997 through December 2007, approximately 16,540 cranial surgeries were performed by 25 neurosurgeons. These included elective as well as emergency and trauma cases. Of these cases 82 (0.5%) were performed to treat postoperative infection in 50 patients. All 50 patients underwent their original surgery at the authors' institution. The median age was 51 years (range 2-74 years). There were 26 male and 24 female patients. The most common offending organism was methicillin-sensitive Staphylococcus aureus, which was found in 10 of 50 patients. Gram-negative rods were found in 15 patients. Multiple organisms were identified in specimens obtained in 5 patients. Six patients had negative cultures. Most craniotomies leading to subsequent infection were performed for tumors or other mass lesions (23 of 50 patients), followed by craniotomies for hemorrhage and vascular lesions. Almost half of the patients underwent > 1 cranial operation before presenting with infection.

CONCLUSIONS

Postoperative infection after cranial surgery is an important phenomenon that needs immediate recognition. Even with strict adherence to sterile techniques and administration of antibiotic prophylaxis, a small percentage of these patients will develop an infection severe enough to require reoperation.

Postoperative intracranial neurosurgery infection rates in North America versus Europe: a systematic analysis

BACKGROUND

Postoperative wound infection (PWI) after intracranial neurosurgery remains a significant worldwide problem, resulting in substantial morbidity/mortality if not combatted quickly and energetically. Although the danger of PWI is universally recognized, the reported incidence of PWI after intracranial neurosurgery remains variable, ranging from 1% to 8% in published series. The impact of geography on this reported variability has not been previously investigated. To address this issue, published comprehensive intracranial neurosurgery series were reviewed, segregating findings geographically between North American and European series.

METHODS

A comprehensive literature search was conducted using the Entrez gateway of the PubMed database. Studies conducted in North America and Europe reporting the incidence of PWI after intracranial neurosurgery were subjected to a thorough review. Data from studies meeting inclusion criteria (minimum of 500 cases with no systematic exclusion of procedures) were categorized by origin (North American/European) and design (retrospective/prospective). Recorded incidences were then compared using chi(2) analysis, and estimates of the relative risk of PWI were calculated.

RESULTS

Seven studies (4 North American, 3 European) met all of the inclusion criteria, with a 2.6-fold greater PWI incidence reported in the European studies (P < .001). The relative risk of PWI for Europeans versus North Americans per operative case was 2.60.

CONCLUSION

PWI after intracranial neurosurgery was nearly 3 times more likely in European versus North American studies. These findings should be considered by clinicians when estimating the risks of intracranial neurosurgery, and highlight the need for future prospective studies to provide evidence-based explanations for these differences.

THE SURGICAL MANAGEMENT OF INFECTIONS INVOLVING THE CEREBRUM

OBJECTIVE

Infection involving the cerebrum is a true neurosurgical emergency that requires rapid diagnosis and appropriate surgical and medical intervention to achieve good clinical outcome.

METHODS

Because of the potential for devastating neurological sequelae, it is imperative that neurosurgeons be involved in the diagnosis and management of these serious conditions once an infection is suspected. With the advent of computed tomography and magnetic resonance imaging, it is now possible to detect an infectious process early in its course and follow the response to therapy. Although significantly more effective than in the past, antimicrobial therapy alone is insufficient to eradicate most intracranial infections, especially in the presence of compression or displacement of the cerebrum. Surgery remains an essential part of the management of intracranial infection because of its ability to provide immediate relief from pressure on neural structures and thereby result in clinical improvement.

RESULTS

The most common infections affecting the brain, namely, cranial epidural abscess, subdural empyema, brain abscess, viral infection, tuberculosis, and neurocysticercosis, can each be associated with significant mass effect on the cerebrum that is greatly reduced through surgery. This relief, in combination with newer antimicrobial agents that have an improved ability to cross the blood brain barrier, has led to a reduction in the infection-related morbidity and mortality rates associated with intracranial infections.

CONCLUSION

Combining advanced imaging and surgical techniques in the form of intraoperative magnetic resonance image-guided neurosurgery may further enhance clinical outcomes in these once uniformly fatal diseases.

Fever and Periorbital Edema: A Review

Fever and periorbital swelling are the manifestation of a broad array of diseases. Among them are emergency situations, which need prompt physician input. Swiftly formulating a differential diagnosis approach is crucial. Diseases causing fever and periorbital edema are either local or systemic. Nevertheless, their impact can be systemic if they evade diagnosis. Infectious diseases and non-infectious diseases (inflammatory and allergic diseases, autoimmune diseases, neoplastic diseases, and trauma) can all lead to fever and periorbital edema. A meticulous history and physical examination in association with targeted tests against the presented spectrum of diseases (specific serological tests, radiological tests, cultures taken from the surface of the periorbital area and other relevant areas, and skin biopsy for histological and microbiological examination) will clarify the diagnosis.

Postoperative Central Nervous System Infection: Incidence and Associated Factors in 2111 Neurosurgical Procedures

BACKGROUND

Postoperative central nervous system infection (PCNSI) in patients undergoing neurosurgical procedures represents a serious problem that requires immediate attention. PCNSI most commonly manifests as meningitis, subdural empyema, and/or brain abscess. Recent studies (which have included a minimum of 1000 operations) have reported that the incidence of PCNSI after neurosurgical procedures is 5%-7%, and many physicians believe that the true incidence is even higher. To address this issue, we examined the incidence of PCNSI in a sizeable patient population.

METHODS

The medical records and postoperative courses for patients involved in 2111 neurosurgical procedures at our institution during 1991-2005 were reviewed retrospectively to determine the incidence of PCNSI, the identity of offending organisms, and the factors associated with infection.

RESULTS

The median age of patients at the time of surgery was 45 years. Of the 1587 cranial operations, 14 (0.8%) were complicated by PCNSI, whereas none of the 32 peripheral nerve operations resulted in PCNSI. The remaining 492 operative cases involved spinal surgery, of which 2 (0.4%) were complicated by PCNSI. The overall incidence of PCNSI was 0.8% (occurring after 16 of 2111 operations); the incidence of bacterial meningitis was 0.3% (occurring after 4 of 1587 operations), and the incidence of brain abscess was 0.2% (occurring after 3 of 1587 operations). The most common offending organism was Staphylococcus aureus (8 cases; 50% of infections), followed by Propionibacterium acnes (4 cases; 25% of infections). Cerebrospinal fluid leakage, diabetes mellitus, and male sex were not associated with PCNSI (P>.05).

CONCLUSIONS

In one of the largest neurosurgical studies to have investigated PCNSI, the incidence of infection after neurosurgical procedures was <1%--more than 6 times lower than that reported in recent series of comparable numerical size. Cerebrospinal fluid leak, diabetes mellitus, and male sex were not associated with an increased incidence of PCNSI. The results from this study indicate that the true incidence of PCNSI after neurosurgical procedures may be greatly overestimated in the literature and that, in surgical procedures associated with a high risk of infection, prophylaxis for S. aureus and/or P. acnes infection should be of primary concern.

Vascular and Parameningeal Infections of the Head and Neck

Vascular and parameningeal infections of the head and neck are rare but frequently life threatening. These infections include intracranial and extracranial septic venous thrombophlebitis, arterial mycotic aneurysms and erosions, subdural empyema, and epidural abscesses. They usually arise as complications of otogenic, oropharyngeal, or paranasal sinus infections, and management involves an aggressive combined medical-surgical approach.